In some communication systems, it is not unusual for a hardware or software problem to disrupt communication between two or more callers. Some telecommunication equipment may include redundant capabilities in order to improve reliability. For example, the equipment may duplicate critical components within a single system, such as processors and power supplies. While this technique may provide against failures of components, it does not protect against a complete equipment failure of the single system or lack of accessibility or availability of the single system. A fire, earthquake, external power failure, or other disruption may cause a failure of the single system or result in the single system being unavailable or inaccessible for a period of time. Such a disruption may halt calls in progress and prevent new calls from taking place.
In some scenarios, a redundant stand-by system at a geographically different location from a primary system may provide a higher degree of overall system availability and reliability. Unfortunately, maintaining call state databases, system configuration and other information continuously synchronized between the two systems requires a considerable amount of real-time data traffic between the two systems. In voice communication systems, the requirement for continuous data communication cannot be implemented in a realistic or real-time manner as the amount of data being generated and transferred between the two systems is too large. This problem is exacerbated when an IP (Internet Protocol) network is used as part of the communication system
It would be advantageous to provide a method and apparatus that overcame the drawbacks of the prior art. In particular, it would be desirable to provide a method and apparatus that allowed a stand-by server to provide redundant capabilities for conducting calls and maintaining calls in progress without having to update call state databases continuously. In addition, it would be desirable to provide a method and apparatus that allowed such redundant capabilities for communication systems using one or more IP networks.